This invention relates to an apparatus and a method for controlling the preheating temperature of equipment having a preheating device for start-up. The invention relates particularly to an apparatus and a method for controlling the preheating temperature to ensure that preheating will end within a specified start-up time.
To record ultrasonic diagnostic images, thermal recording is currently employed that uses thermal films having a heat-sensitive recording layer formed on a transparent film base. Since thermal recording has several advantages such no need for wet development and the ease of handling, its application is not limited to the recording of small-size images as in ultrasonic diagnosis but has recently expanded to uses such as MRI and X-ray diagnoses that require large and high-quality images.
The apparatus for performing heat-sensitive image recording is commonly called a thermal printer and has a thermal head to perform heat-sensitive image recording on the thermal film. In order to record a sharp ultrasonic diagnostic image on the thermal film by device of the thermal head, it is necessary to control the temperature of the thermal head and to this end, the thermal head is equipped with a preheating device for raising the temperature to a specified level, as well as a cooling fan for cooling the thermal head if its temperature is too high.
The preheating device is commonly an electric heater, or a heat source of a type that produces heat upon current impression The life of the heat source is considerably shortened if current is impressed continuously for a prolonged period or if high voltage is applied in order to attain higher temperatures. To avoid this problem, heating is generally performed by impressing an electric current according to a specified pattern that consists of intermittent heating at constant voltage. However, if this approach is taken, the required preheating time varies with the temperature prior to heating and it is difficult to predict the waiting time, or the time the equipment requires to become operable after the power supply is switched on.
In addition to the thermal printer for recording ultrasonic diagnostic images, many models of medical equipment have a device of preheating to a specified temperature before they start to operate. However, such preheating device is only capable of preheating according to a specified pattern after the power supply is switched on and no consideration has been given to controlling the time taken by the preheating step. The waiting time is difficult to predict and even in a case of emergency, an unduly prolonged preheating time is spent.
The present invention has been accomplished under these circumstances and has as an object providing an apparatus for controlling the preheating temperature such that preheating ends within a specified start-up period to ensure positive prediction of the waiting time so that the lapse of an unduly prolonged preheating time can be avoided and which, in a case of emergency, sets a shorter preheating time to minimize the period for which the user has to wait.
Another object of the invention is to provide a method for controlling the preheating temperature with the above-described apparatus.
In order to attain the object described above, the first aspect of the present invention provides an apparatus for controlling preheating temperature of equipment having a device to be preheated and a preheating device for start-up, the preheating device including a heat source and a heat source control device which has a plurality of heating patterns to control the heat source, the apparatus comprising: a temperature measuring device for measuring current temperature of the device to be preheated within the equipment; a computing device for calculating a predicted time that is required by the preheating device to preheat the device from the current temperature to a preset temperature; a comparison device by which the predicted time as calculated by the computing device is compared with a specified start-up time; and a selecting device for selecting from the plurality of heating patterns within the heat source control device a heating pattern that makes the predicted time shorter than the start-up time.
In order to attain another object described above, the second aspect of the present invention provides a method for controlling preheating temperature of equipment having a device to be preheated and a preheating device for start-up, comprising: a current temperature measuring step for measuring current temperature of the device to be preheated within the equipment at start of preheating the device to be preheated by the preheating device; a selection step for selecting one of the heating patterns possessed by the preheating device within the equipment; a computing step for calculating a predicted time that is required to preheat the device to be preheated from the current temperature to a preset temperature; and a comparison step for comparing the predicted time with a specified start-up time; wherein if the predicted time is longer than the specified start-up time, another heating pattern is selected and the predicted time is calculated again so that an appropriate heating pattern is selected by repeating respective selection, computing and comparison steps until the predicted time becomes shorter than the specified start-up time.
Preferably, the specified start-up time can be set at a desired value.
Preferably, the equipment is medical equipment.
Preferably, the preheating device is one for the medical equipment.
Preferably, the device to be preheated is a thermal head in a thermal printer which prints out image data being output from the medical equipment and the preheating device is one for preheating the thermal head.